2. amps-preamps
  3. 1210351569

Amp upgrade question

I have a passive bi-amp w/ two CJ SS amps. I can pull this off because they have the same gain, sensitivity and input impedance. The amps are an MF-2500 upgraded to a 2500A running LF and an MF-2100 running HF. 250 WPC on the LF 100 WPC on the HF. I'd like to get better performance on the HF. It's not that I need it louder so much as wanting it better. It's not bad now by the way.The question is should I throw $500 at an upgrade by a great shop (new Cardas Rhodium RCA's,speaker binding posts, silver wire, faster/better PS diodes) or just buy an MF-2250 which show up here for 900-1200 usually. It is a more recent amp with better quality and 120 WPC which would also be the exact match needed for my passive bi-amp in terms of input imp., sens, gain. I would love to have tubes for my HF amp but feel I would need a power amp w/a gain control as finding those same needed input specs would be tough. I use a passive line stage. Thanks in advance for any suggestions.

ET
electroid
6 responses Add your response
electroid OP
283 posts
 
Thanks Aball-I've got a CJ PV-1 w/2AR upgrade and other tweaks along with the 2100 which I will try to sell. I can always go back to just the 2500A till I get the bucks and find the "right" amp for the top. Too bad I sold my Eico HF-60's about 5 years ago.

ET
aball
2,016 posts
 
Yeah, it is hard to beat horizontal biamping. It presents a way better load to the amps than first seems apparent.

My suggestion would be sell off your 2100 and get an older McIntosh MC275 or a vintage MC240. The older ones have gain controls that work super well for passive horizontal biamping, which is exactly what I do in my system with a MC240 and Kora monoblocks on the bass.

The transparency and resolution of those McIntosh tube amps when only running 200Hz on up (or so) is about the finest I have ever heard in my life. Totally worth the money even if you have to save up for it.

Arthur
electroid OP
283 posts
 
I used to run the 2500 full range, then added bi-wire(big help) and then finally adding the 2100 which really improved coherence and added dimension to the soundstage. An overall improvement for sure. HF was about identical in tone quality, no downgrade to my ears. I use a few different sets of speakers: Maggies and a Polk SDA SRS series. Sold my Quads. Loved em but too big a room and I'm a bit of a loud freak and listen to bass heavy stuff often. Things are not bad at all now. I just wonder if they could be better. The 2100 is an older design. Originally it had a hard wired 18 gauge power cord. I put an IEC on it and a good cord, that helped for sure. Also I use a passive linestage so longer interconnects is a no no. I really would love tubes if I could afford a power amp w/ a gain control that had 100WPC.

ET
bdgregory
1,712 posts
 
what speakers are you driving? Have you tried simply using the 2500A by itself in biwire? with the juice it has I'd expect it to do better full range than the biamp arrangement you currently have. At one time I used dual CJ MF2100s vertically biamped - but the benefit was based on the fact it's short on power.

If it were me, I would first try the single MF2500a, and if I really thought I needed more juice - get another MF2500a and go vertical biamping. This also permits shorter speaker cable runs if you position the amps next to the speaker.

The other option would be to try tubes on the top. Many tube amps have a volume pot that permits balancing out the volume, but my attempt at this was less than fully satisfying (ie it was more trouble than it was worth).
samujohn's avatar
samujohn
291 posts
 
Have you tried simply exchanging the amps to see if you like the HF of the 2500A better? I upgraded from a 2300A to a 2500A and I thought it a worthwhile improvement.
I am also skeptical of third party upgrades to something as evolved as a CJ design. Better parts may not lead to better sound, because the designer made his choices based on sound as well as price.
tweak1
3,658 posts
 
Too many variables to hone in what exactly is the problem. I would recommend checking into Clear Day solid core silver shotgun speker cables. They did wonderful things for my HFs as well as every other music parameter. Best of all, they are affordable. He advertises here so search for clear day speaker cables
Log in to respond
More to discover
80x80
VAC 300.1 Tube Amplifier
80x80
Dan D'Agostino Momentum HD
80x80
Aurorasound PADA-300B Hybrid Mono-blocks